They raced up the stairs and through the large doors of the dining hall. As if nothing had happened in the meantime, the passengers still sat quietly. It was obvious that the changes in the movement had caused concern. No one spoke and most of the children sat with or near the adults, huddled together in corners.

"It's going to be alright," The Doctor said clearly, "but we need to work together to get this ship to its destination and quickly."

"What's happening?" a woman called back, "have you hi-jacked this ship?"

"No!" The Doctor looked up from the key in his hand. "Well, in a sense, I might be about to. This ship is having problems and I can fix them. You need to trust me on this, all of you, because you'll need to help me. Think about it. Have any of you seen any of the crew you know in the last few hours? They need your help too."

"Are we going to crash?"

"No. Absolutely not. Now...listen to me. First of all, I need you all to focus. Think of Vira and why you want to go there. Just one really good reason."

Peter couldn't blame his fellow passengers for looking as incredulous as he felt.

"What if we don't have one?" a young girl asked.

"You do," he told her, "even if it's curiosity, or the fact that someone loved you enough to want you safe. Get that thought and hold on to it. Really concentrate. I know it sounds daft but you've got to trust me."

He turned solemnly to Peter.

"You have a reason now. Don't you?"

Shakily, Peter nodded, terrified at the Doctor's insight into his mind.

"Collective telekinetic skills can be a powerful thing, believe me. Combine with collective thought and huon particles and you never know what they can do. Virans and humans combined!"

The ship buckled suddenly. Peter had almost gotten used to its trembling and shudderings in the last hour or so but this one nearly knocked him to the ground. He found himself clutching the Doctor's arm. Every light in the room flickered and died. Someone screamed and a crazy thought entered his head that for the rest of his life (however long that might be), he might never get rid of the sound of that scream.

"What happened?" he asked, "are we crashing?"

"No." He felt the Doctor's hands on his shoulders, steadying him. "The machine...the person being used as the machine. They've crashed." He sounded shaky. Peter watched as he aimed his device at the lights. A faint glow appeared from each one, just enough to see by.

"Show me your key," he said to Peter.

Peter lifted the key, breathing in sharply as his fingers touched it.

"I didn't do anything to it, honest." Even in the semi-dark, he saw it glow.

"It's boiling hot," he told him.

The Doctor took the key carefully from him and held it out. With every second, it seemed to glow brighter.

He stared at the key as if he couldn't take his eyes off it.

"This is good," he said softly, "we can save everyone else now."

But his face looked shattered. With a hand that shook slightly, he reached into his pocket for the notebook that had amused Donna so much and wrote something on it.

He faced the terrified crowd again.

"Keep that thought in your heads. Please. It's very important." He lowered his voice. "Come on, Peter.

...

"Jack? Are you alright?" Donna watched in horror as Jack stumbled, leaning against the control to steady himself. She moved towards him, aware of the air thickening as she did, as if about to attack her. Jack waved her back.

"Yeah, I'm fine." He didn't sound it.

"It's not working, Sir," Private Newman said, typing frantically into one of the keyboards beside him.

"Give it time," the Professor said.

"We don't have time! It's minutes now, Sir! We need to leave!"

"Gather the staff," the Professor said and Private Newman pressed a button. An alarm rang out somewhere in the distance. "By the time they assemble, the machine will be operational."

"If not..." Jack was gasping. "You'll have no home to go to."

"Quiet, please." The professor handed him another vial.

"Stop it!" Donna shouted. "He can't take anymore!"

Jack winked at her. "Are you calling me weak? I can drink anything!" But as soon as he finished the sentence, he slid to the ground.

"Jack!"

"Maybe she should take some too," Private Newman said, "two instead of one. It just might take the extra."

"Don't go near her!" Clara shouted, running to stand in front of Donna. The Professor pushed her roughly aside.

As he approached her with the vial, Donna felt her skin burn, as if drops of boiling liquid were falling onto her, one by one. She struggled to take a breath, turning her head frantically in desperation. She felt the glass being pushed into her hand. Clara ran forward again and took it from her.

"Leave her alone!"

Private Newman ran forward, grabbed Clara and pushed her down again. She landed awkwardly on the hard ground and lay still. The vial cracked and fell, liquid oozing away from it. A thin steam floated upwards from it.

Private Newman grabbed the Professor's arm and pulled them both away from the spilt liquid.

"We're not in short supply, my dear, don't worry," the Professor said smoothly as he moved toward the cupboard. Donna glanced at Jack in desperation. He was trying to stand and in one hand, she could see the outline of the psychic paper that had amused her so much. Had the Doctor communicated something?

Her hands were getting redder by the moment. Jack's eyes were open and he was reaching for the controls nearest to him, trying to pull himself fully upright.

"Here we go." They were both approaching her now, a new vial in the Professor's hand. Donna forced herself to go still. She was shaking, whether purely from fear or the effort to breathe, she wasn't sure. This time, he brought the vial to her lips. Jack, leaning as far as the ropes would let him, had almost reached the controls with the tips of her fingers.

Donna opened her mouth and raised her hand at the same time. She pushed the vial as hard as she could, tipping a bottom corner of it with her fingers. She buckled backwards, pushing with all her might.

The vial fell. She stepped back, trying hard to get as far back as she could. But there was no need. It had fallen over the two men.

There was a dead silence. Donna fell back against the wall. The steam from the liquid was choking her. But it was also choking the two men. Shadows seemed to fall over them. Their faces were deadly pale. Private Newman shouted out once and staggered forward towards another control. He pulled a panel out to reveal what looked like a square tile on the floor.

The door opened and the room was filling with people wearing the uniform of the crew. They were all pressing buttons on their wrist devices and moving to form a line in front of the mat. Some of them stared in concern at the Professor who was cowering on the ground but most were too intent on the actions of Private Newman.

"You're safer here," Jack said to them. "Listen! It's not safe anymore. I was a Time Agent. I know how this works!"

One or two people spared him a glance but one by one, they moved forward to stand on the square. Two of them pulled the Professor with them by his arms. They all stepped on cautiously, then moved forward to huddle together with the others. When they were all within the confines of the square, Private Newman reached over and pressed a button.

"Impact in 50 seconds," he said.

"The asteroid!" Clara gasped.

"Don't!" Jack shouted to them. "Seriously, it's not safe! You don't know where you're going!"

None of them responded.

Jack staggered forwards, trying to reach the controls again but before he got there, they all vanished on the spot.

"They've got away..." Donna whispered.

"Not quite." Jack's face was grim. "Wait."

The square buckled violently, even though no one stood on it anymore.

"Are we crashing?" Donna asked as Clara grabbed hold of her.

There was a flash of light and Donna gasped as an outline of a familiar creature appeared on top of it...one of those dark birds that had chased them in Churington, when Clara's mistake had caused time to go haywire. She covered her face, knowing that running was impossible.

The whole ship trembled and she buried her head, thinking of the passengers, of the Doctor and Peter walking away from them and the blond girl catching her eye on the staircase.

"It's ok." Jack's voice was strained. "Donna! Look."

She raised her head and the creature was gone. The rumbling sounds were quieter. At the other end of the room, Clara was sitting up slowly, looking around with wide eyes.

"Are those creatures all over the ship?"

"No." Jack leaned against the controls, looking sick. "I make a better Paradox machine than I thought I would!"

"How did you know that liquid would harm them?"

"I didn't. Not really. But it was the only weapon you had! And I thought...huon particles...Paradox machine. They are a paradox." He groaned softly.

"What was the control you pressed?"

"Disabled the Paradox machine for once and all. The Doctor...wrote it." He sounded as if speaking was an effort. "Might give that poor soul a chance. But it's banished them." He looked at the square tile. "Transmat couldn't operate. They've cancelled themselves out. All of them."

"You tried to warn them."

"Yeah." He closed his eyes for a moment.

"We haven't crashed."

"No. Can't you hear the engine? Something's pulling us away."

"Come on," he said finally, moving unsteadily towards Donna and helping her gently to her feet. "You need to get out of here. Come on, Clara. Can you walk?"

"Probably better than you can." Clara was still staring at the spot where the Time Agents had stood, making their escape. She bowed her head and followed them.

...

Peter couldn't speak. He stared around, then stared around again. If he had once thought that nothing more would ever surprise him, he'd been so wrong.

"As you've noticed," the Doctor was saying, "it's bigger on the inside!" He patted a wall of the ship with great affection.

Peter nodded, and struggled to speak.

"You and Donna...you travel in this?"

"Yes." The Doctor came around the controls and stood in front of Peter, staring intently at him.

"Peter, it's important you understand this. I can't ask you to come and travel with us. I'm sorry, and I'm sorry that I can't explain why. Well, in a way I can. It wouldn't be fair on you, for a start. The people who travel with me, whether or not, they're happy with them, they have established lives back on Earth or wherever. You haven't. And I can't take someone who has nowhere to come from and nowhere to return to."

Peter nodded. Yesterday, he thought, he would have shouted. Because in a way, he'd wanted the Doctor to save him from the moment they met.

"You'll stay me though, will you?" He looked away as he asked. "Just until I know who I'm going to live with."

"Of course we will," the Doctor replied. He pulled a lever and pressed down hard.

"Peter? Press that red button, will you? And hold down that lever beside you."

"What are you doing?"

"Peter." The Doctor smiled at him. "We're towing an asteroid! So, that button, if you would?"

Peter did as he was told. He kept his hand steady and pressed as hard as he could as if the movement was the most important thing he had ever done.

...

They burst into the broom closet and stopped dead, nearly crashing into one another.

"Has it been taken?" Clara asked.

"Yes!" Jack sounded gleeful.

"Let's hope it's the Doctor that took it," Donna said.

They walked slowly down the hallway and back down towards the large dining room. As they pushed open the door, Donna was amazed at the silence within. The lights were turned down low and the people sat silently, in groups, looking as though they were in a trance.

"Are they alright?" she whispered.

Catherine suddenly stood up and crept towards her.

"It's working," she whispered. "I know it's working. I have to say, I thought your husband was mad. But whatever he did, it's having an effect."

"What did he want you to do?"

"Think about Vira and why we want to go there. Do you know, I think we're actually moving again!"

"Yeah, I think we are." She looked around the surreal scene of adults and children whispering and dreaming together in the midst of now chaotic room. Broken china lay on the floor and the dim lights made the plush room look grey and gloomy.

"We now have a crew!" Jack remarked.

Donna turned around, realising that they had walked past two of the crew on her way into the room without even noticing. Recognising Frida, she ran up to her.

"You're back! Where were you?"

Frida looked slightly disorientated.

"There was an emergency," she said faintly, "I don't know. Maybe we shut down for a while...or fumes knocked us out. Thank goodness everyone is ok!"

"Yeah." Donna walked back to Jack.

"Where were they?" Clara was asking. "Banished?"

"Yeah. The Time Agency controlled the Paradox machine to let the ship move back in time and cancel out the crew. They're back now that it's destroyed." For a few seconds, they were silent.

"We should find that person now," Donna said, feeling a sharp stab of fear.

"Yeah. I hope it's not..." Jack looked at Clara.

"Me too," Donna whispered.

...

The Doctor was looking intently at a screen in front of him. The movement of the TARDIS seemed to have slowed a bit. Peter felt himself relaxing, feeling rather than hearing the steady hum of the ship.

"I wish our ship had been like this one," he said out loud.

"Donna thought that too. She wasn't happy in your ship from the moment we came on board. Mind you, with good reason as it turned out."

"Do you think she's ok?"

"She'll be fine," the Doctor said. "When Jack says he'll keep someone safe, I know he will."

"Does he travel with you too?"

"Sort of. Sometimes. Our paths cross quite a bit!"

"It must be..." Peter trailed off, looking around him in wonder. "Do you think there's anything on Vira like this? I mean...time travel and going to space?"

"There's got to be, hasn't there? They invited you lot. Come here."

Peter followed the Doctor to the door, jumping back slightly as he started to open it.

"Is that safe?"

"Yeah!" The Doctor pulled the door open and Peter moved tentatively to stand beside him. He looked out and for a second, thought he was going to faint.

"Ok?"

"Yeah..." He stared at the night sky in front of him and its distant glow of colour and light.

"Is that a planet?"

"That's your asteroid, Peter," the Doctor said softly.

"It's huge!"

"Yes."

"It'll kill everything on Earth, won't it?"

The Doctor was silent for a moment.

"Peter. You've been very patient with all the questions we couldn't answer so I'm going to tell you something. And you can't tell a soul. They'll know soon enough anyway. This is between us, right?"

Peter nodded, swallowing hard.

"It's not to going to hit Earth. I've pulled it out of the way. I could have done it sooner, of course I could. I've always known it wouldn't hit. But I couldn't take the chance that something else was supposed to happen to stop it colliding. It's all part of time travel."

"So really, we never had to go to Vira?" Peter held on the door, suddenly feeling unreal.

"You did and you do. Peter, this is one of the most important things that happens in your history. And some day, that'll make more sense than it does now. You've started a process that will save the Earth many times over in the future. You can only survive on your own for so long."

"I know," Peter whispered.

"I don't underestimate the cost to you," the Doctor said gently.

"Everyone else did."

"Everyone else didn't know what it was like."

Suddenly, hardly making a decision to, Peter found himself sobbing. And it wasn't embarrassing. And it wasn't stupid. Because the Doctor's hand on his shoulder and the vast expanse of emptiness outside seemed to say to him that he'd be a fool not to.

When he began to calm, he realised that for the first time in weeks, he could breathe freely and that made him think of Donna.

"We're heading back to the ship," the Doctor said, handing him a tissue. He went to close the door and then opened it once more.

"Just look down there."

Peter looked. The lights glistened now, taking shape, rising and falling in the gloom.

"That's a planet."

"That's Vira."

...

It was easier to breathe in the treasure room and that thought made Donna feel very uneasy. Surely if the effects of the particles were dissipating, it wasn't good for the person. Person. She couldn't think any more specifically than that. She knew that the others felt the same. Clara's lips were pursed and her face was pale. Jack kept beginning sentences and stopping in the middle of them.

Jack sighed in frustration as they moved to the next room.

"We'll have to search every room. And even then..." He stopped suddenly. "Look."

He pointed to a spot near another desk of controls. Beside it, was a small white bed. A small white bed with ropes. Frayed ropes. Clara gave a small gasp.

"This is where she was kept."

Beside the bed was a table full of empty vials and what looked like a heart monitor.

"She can't have got far," Jack said somberly.

They left the room and walked up the hallway. Donna stopped suddenly, looking at the staircase.

"What is it?" Jack asked.

"My arms..." She held out her arms to them, red blotches quickly taking shape.

"I'd be allergic to her, wouldn't I?"

"Yes!" They ran up the stairs together and at the top, was a familiar sound, the most beautiful familiar sound, Donna had ever heard.

"The TARDIS!"

They burst into the broom closet as the TARDIS began to materialise, almost knocking each other down in their haste to get in.

Donna was the first to see her, raising her head slightly as the ship came into view then collapsing downwards into total stillness. She thought she screamed. The door of the TARDIS opened.

"Doctor!" Donna screamed, unable to say anymore. She saw him look at her, then at the ground in front of him. Heard Peter say something and take her arm. Felt Jack's arms around her as he pulled her from the room.

And the Doctor's voice, cracked and strained.

"Jenny."